#!/usr/bin/perl

@r = ((7,12,17,22) x 4 , (5,9,14,20) x 4 , (4,11,16,23) x 4 , (6,10,15,21) x 4);

$k[$_] = (int(abs(sin($_+1))*(2**32))) for 0..63;

$H0 = 0x67452301;
$H1 = 0xefcdab89;
$H2 = 0x98badcfe;
$H3 = 0x10325476;

print "> ";
@msg = map(ord, split // , <>);
pop @msg;

$msgbin .= 0 . sprintf('%b',$msg[$_]) for 0..$#msg;
$length = sprintf('%b',length $msgbin);
$length = 0 . $length while length $length < 64;
$msgbin .= 1;
$msgbin .= 0 until length $msgbin == 448 % 512;
$msgbin .= $length;

for ($i=0,$j=0;$j<16;$i+=32,$j++) {
   $w[$j] = (unpack("N", pack("B32", substr("0" x 32 . (substr($msgbin,$i,32)), -32)))) % (2**32); 
}

$a = $H0;
$b = $H1;
$c = $H2;
$d = $H3;

for $i (0..63) {
   if ($i >= 0 && $i <= 15) {
      $f = (($b & $c) | ((~$b) & $d)) % (2**32);
      $g = $i;
   } elsif ($i >= 16 && $i <= 31) {
      $f = (($d & $b) | ((~$d) & $c)) % (2**32);
      $g = (5*$i + 1) % 16;
   } elsif ($i >= 32 && $i <= 47) {
      $f = ($b ^ $c ^ $d) % (2**32);
      $g = (3*$i + 1) % 16;
   } elsif ($i >= 48 && $i <= 63) {
      $f = ($c ^ ($b | (~$d))) % (2**32);
      $g = (7*$i + 1) % 16;
   }

$temp = $d % (2**32);
$d = $c % (2**32);
$c = $b % (2**32);
$b = ($b + (($a + $f + $k[$i] + $w[$g]) << $r[$i])) % (2**32);
$a = $temp % (2**32);

}
$H0 = unpack("H8", pack("N", ($H0 + $a)));
$H1 = unpack("H8", pack("N", ($H1 + $b)));
$H2 = unpack("H8", pack("N", ($H2 + $c)));
$H3 = unpack("H8", pack("N", ($H3 + $d)));

$digest = $H0.$H1.$H2.$H3;
print "> $digest\n";